Colloidal dispersion systems in physical pharmaceutics: Recent advances and applications

Colloidal dispersion systems play an important role in physical pharmaceutics and modern drug delivery research. Colloids are heterogeneous systems in which one phase is dispersed uniformly into another phase with particle sizes generally ranging from 1 nm to 1000 nm. These systems improve drug stability, solubility, bioavailability, and therapeutic effectiveness. Pharmaceutical colloids include sols, gels, emulsions, suspensions, aerosols, foams, and nanosystems such as liposomes and nanoparticles. The physicochemical properties of colloids, including Brownian movement, zeta potential, electrophoresis, and electrical double layer, significantly influence formulation stability and performance. Recent advancements in colloidal drug delivery systems have enhanced targeted drug delivery, controlled release, and patient compliance. Colloidal dispersions are widely utilized in oral, topical, ophthalmic, pulmonary, and parenteral formulations. Nanotechnology-based colloidal carriers have also emerged as promising systems for anticancer therapy, vaccine delivery, and herbal drug formulations. This review discusses the classification, preparation methods, properties, stability, evaluation parameters, and pharmaceutical applications of colloidal dispersions along with recent innovations and future perspectives in physical pharmaceutics.